This invention relates to glass-reinforced theremoplastics. Improvement of polymer properties is a dominant factor in the development and production of olefin polymers. Several methods have been employed to improve various polymer properties.
Polymers with relatively high melting points, such as stereoregular polymers of branched higher alpha-olefins, have been developed. These polymers are useful in high temperature applications such as microwave packaging. Improving the performance and/or properties of these polymers could expand the variety of uses of these polymers.
Reinforcing agents such as glass fibers can be incorporated into the polymer to improve the mechanical properties and/or the heat resistance of the polymer. However, merely mixing the glass fibers and the polyolefins together can result in weak bonding between the glass fibers and the polyolefin. One solution is to have a more bondable component grafted onto the polymers to facilitate reinforcement with glass fibers and other generally infusible reinforcing agents.
Polymers of branched higher alpha-olefins have been modified with grafting reactions to incorporate functional chemical moieties to improve the adhesion between the alpha-olefin matrix and the glass reinforcement as has been disclosed in U.S. Pat. No. 4,888,394, Dec. 19, 1989.
Glass fiber reinforcement products are usually sized either during the fiber formation process or in a posttreatment. Sizing compositions for use in treating glass fibers usually contain a lubricant, which provides the protection for the glass fiber strand; a film former or binder that gives the glass fiber strand integrity and workability; a coupling agent that provides better adhesion between the glass fiber strand and the polymeric materials which are reinforced with the glass fiber strand; and other additives such as emulsifiers, wetting agents, nucleating agents, and the like.
Sizing compositions which can be used for treating glass fibers for improved adhesion between the glass fiber strand and relatively low melting point polyolefins, such as polyethylene and polypropylene, are known. The polyolefin may be modified partially or entirely with an unsaturated carboxylic acid or derivative thereof. But there is still a need for improved adhesion between glass fibers and high melting point stereoregular polymers of branched higher alpha-olefins or stereoregular polymers of branched higher alpha-olefins which have been modified with unsaturated silanes, carboxylic acids, or derivatives thereof.